U.S. patent application number 10/825371 was filed with the patent office on 2004-11-04 for spray element for a spray head.
This patent application is currently assigned to Oskar Frech GmbH + Co. KG. Invention is credited to Erhard, Norbert, Pschenitschni, Hubert.
Application Number | 20040217212 10/825371 |
Document ID | / |
Family ID | 32892921 |
Filed Date | 2004-11-04 |
United States Patent
Application |
20040217212 |
Kind Code |
A1 |
Erhard, Norbert ; et
al. |
November 4, 2004 |
Spray element for a spray head
Abstract
In a spray element for a spray head for spraying the molds of
pressure casting machines, a control piston for the release of the
parting agent supply is disposed beside the spray nozzle and a
connecting passage opens in a chamber of the housing in which one
end of the control piston is sealingly guided, while its second end
lies with a sealing ring before a chamber fed with parting agent.
In the case of the application of control air the sealing ring is
shifted out of its cylindrical section 26 into the chamber, so that
the feed of parting agent to the spray nozzle is released. If the
control air is shut off, then the sealing ring closes the delivery
of the parting agent, and the second, larger end of the control
piston exercises upon its return movement a reverse suction effect
on the connecting passage. Any after-dripping of parting agent is
securely prevented.
Inventors: |
Erhard, Norbert; (Lorch,
DE) ; Pschenitschni, Hubert; (Winterbach,
DE) |
Correspondence
Address: |
CROWELL & MORING LLP
INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Assignee: |
Oskar Frech GmbH + Co. KG
Schorndorf
DE
|
Family ID: |
32892921 |
Appl. No.: |
10/825371 |
Filed: |
April 16, 2004 |
Current U.S.
Class: |
239/569 |
Current CPC
Class: |
F16K 31/1223 20130101;
F16K 23/00 20130101; B05B 7/1263 20130101; B05B 15/654 20180201;
B05B 13/0278 20130101; B22D 17/2007 20130101 |
Class at
Publication: |
239/569 |
International
Class: |
B22D 011/07 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 19, 2003 |
EP |
03009081.5 |
Claims
What is claimed is:
1. Spray element for a spray head, especially for spraying the
molds of pressure casting machines, having a spray nozzle which can
be fed through a valve with the medium to be sprayed and with
compressed air, the valve being provided with a control piston
operated by control air, wherein the control piston plus the spray
nozzle is arranged with both ends in the cylindrical section of a
casing, wherein the first end has a smaller diameter than the
second end and is guided with a sealing ring in a cylindrical
section before a first chamber loaded with the medium to be
sprayed, wherein the second end is guided in a second cylindrical
chamber into which a connecting bore leads to the spray nozzle, and
the side facing away from the first end of the control piston has a
connection for control air, and wherein the distance between the
two ends of the control piston is chosen such that the sealing ring
in the starting position of the control piston lies sealingly in
the cylindrical section and, upon the application of control air to
the second end, enters into the first chamber.
2. Spray element according to claim 1, wherein the housing for the
control piston is provided with a projection to receive the spray
nozzle.
3. Spray element according to claim 2, wherein the projection is
part of the housing.
4. Spray element according to claim 1, wherein all connections for
the control air for the medium to be sprayed and for compressed air
are disposed on the side of the housing which faces away from the
discharge orifice of the spray nozzle.
5. A spray element for a spray head, comprising: a casing including
a first chamber, a cylindrical section, a second cylindrical
chamber, and a connecting bore, wherein the cylindrical section is
placed between the first chamber and the second cylindrical
chamber, and wherein the first chamber is connected a medium to be
sprayed; a valve including first and second pistons, a rod
connecting the first and second pistons, and a sealing ring
disposed on the first piston; and a spray nozzle disposed in the
casing, which can be fed with compressed air and, through the
valve, with the medium to be sprayed, wherein the first piston of
the valve has a smaller diameter than the second piston and can be
guided with the sealing ring in the cylindrical section of the
case, wherein the second piston is guided in a second cylindrical
chamber and divides the second cylindrical chamber into a first
section, in which the rod is disposed, and a second section,
wherein the connecting bore connects the first section of the
second cylindrical chamber with the spray nozzle, wherein the
second section of the second cylindrical chamber is connected with
control air, and wherein the relative position of the pistons is
chosen such that the sealing ring in a starting position of the
valve lies sealingly in the cylindrical section and, upon the
application of control air to the second piston, enters the first
chamber.
6. The spray element according to claim 5, wherein the casing has a
projection for receiving the spray nozzle.
7. The spray element according to claim 6, wherein the projection
is integral with the rest of the casing.
8. The spray element according to claim 4, wherein connections for
the control air, the medium to be sprayed and compressed air are
disposed on a side of the case which faces away from a discharge
orifice of the spray nozzle.
9. A method for making a spray element for a spray head,
comprising: a casing including a first chamber, a cylindrical
section, a second cylindrical chamber, and a connecting bore,
wherein placing a cylindrical section of a case of the spray
element between a first chamber and a second cylindrical chamber of
the case of the spray element; connecting the first chamber to a
medium to be sprayed; disposing a spray nozzle in the casing, which
spray nozzle can be fed with compressed air and, through a valve,
with the medium to be sprayed, wherein a first piston of the valve
has a smaller diameter than a second piston; placing the valve's
first piston with a sealing ring in the cylindrical section of the
case; placing the valve's second piston in a second cylindrical
chamber, thus dividing the second cylindrical chamber into a first
section, in which the rod is disposed, and a second section; the
connecting bore connecting the first section of the second
cylindrical chamber with the spray nozzle; connecting the second
section of the second cylindrical chamber with control air; and
selecting the relative position of the pistons such that the
sealing ring in a starting position of the valve lies sealingly in
the cylindrical section and, upon the application of control air to
the second piston, enters the first chamber.
Description
[0001] This application claims the priority of European Patent
Document No. 03009081.5, filed Apr. 19, 2003, the disclosure of
which is expressly incorporated by reference herein.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] The invention relates to a spray element for a spray head,
especially for spraying the molds of pressure casting machines. The
spray element has a spray nozzle which can be fed with control air
and the medium to be sprayed, and a valve is provided with a
control piston operated by control air.
[0003] DE 32 38 201 A1 discloses a spray element, in which a
spring-loaded control piston is forced by the spring force with its
one end, on which a gasket sits, against a valve seat in front of
which a connecting bore opens to a parting agent connection.
Therefore, if the piston is moved against the spring force by
controlling air, the valve seat opens and the parting agent that is
to be sprayed can issue through a center nozzle opening where it
can be sprayed by means of controlling air jets which surround the
jet of the parting agent.
[0004] A certain disadvantage of such spray elements include that,
when the parting agent feed to the nozzle orifice is shut off,
i.e., when the gasket of the control piston is driven by control
air against its seat, it can lead to unwanted dripping of any
parting agent still present around the discharge opening.
[0005] An object of the invention is to improve a spray element of
the kind referred to above such that any dripping of the medium
being sprayed is prevented by comparatively simple means.
[0006] To achieve the object, in a spray element of the kind
referred to above, the control piston is arranged next to the spray
nozzle with both ends of the control piston in the cylindrical
sections of a housing. The first end has a smaller diameter than
the second end and is guided by a sealing ring in a cylindrical
section before a first chamber fed with the medium to be sprayed.
The second end is guided in a second cylindrical chamber into which
a communicating bore leads into the spray valve and which has on
the side facing away from the first end of the control piston a
connection for control air. The distance between the two ends of
the control piston is chosen such that the sealing ring when in the
starting position lies sealingly in the cylindrical section, and
when control air is applied to the second end it enters the first
chamber.
[0007] By this arrangement, therefore, when control air is applied
to the control piston, the feeding of the medium to the spray
nozzle is released, namely through the second cylindrical chamber,
so that then this medium can be sprayed with compressed air. If,
however, the control air is not applied, then the control piston is
moved by the pressure of the medium being sprayed back to its
starting position in which the feeding of the medium being sprayed
is stopped. Simultaneously, however, the backward movement of the
second end of the control piston increases the volume in the second
cylindrical chamber and thus a certain vacuum is produced, with the
result that the medium held in the bore connecting to the spray
nozzle is moved back, i.e., sucked back so that any after-drip is
prevented.
[0008] In developing the invention, the housing of the control
piston can be provided with an extension to receive the spray
nozzle, this extension can also be a one-piece component of the
housing.
[0009] In a further development of the invention, all connections
for control air, the medium to be sprayed, and compressed air can
be arranged on the side of the housing that faces away from the
discharge opening of the spray nozzle. Thus an easily assembled
modular component is achieved which can be attached in a relatively
simple manner to corresponding spray arms provided with passages
carrying the individual media.
[0010] Other objects, advantages and novel features of the present
invention will become apparent from the following detailed
description of the invention when considered in conjunction with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is an exploded view of a spray head in which spraying
elements according to the invention are inserted.
[0012] FIG. 2 is an enlarged view of a section through a spray
element of FIG. 1 in a plane which is indicated by the section line
II-II in FIG. 1.
DETAILED DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows a spray head, in which a spray element of the
invention can be used. A part 1 of an arm which can be guided for
movement in the direction of the arrows 2 is provided on its bottom
with a plurality of distributor blocks 3 arranged in line with one
another, which are all of identical shape and arranged one under
the other in the direction of the movement 2. The distributor
blocks 3 are arranged tightly one on the other and tightly against
the connection end of the arm 1.
[0014] The arm 1 can be provided in known manner with a
controllable drive, and has in its interior the schematically
indicated through-passages 4, 5, 6 and 7, each serving for the
delivery of parting agent, control air and compressed air. These
through-passages 4 to 7 continue downward through each distributor
block, and a supply passage branches transversely from each of the
passages. The supply passages lead to points 8, 9, 10 and 11 on the
sides of the distributor blocks 3. From there again the connection
to spray nozzles 12 is provided through connecting plates 13 and
flange blocks 14, in some cases also with the interposition of
spacers 15. In this manner it becomes possible to arrange spray
nozzles 12 in various ways in a horizontal plane of one of the
distributor blocks 3 in order to adapt the spray block to the
internal shape of the moving mold halves and stationary mold halves
of a pressure casting machine. It is of course necessary after each
casting operation to spray these mold halves with parting agent or
also to blow them out with compressed air.
[0015] A spray nozzle 12 is, as shown in FIG. 2, arranged in a
projection 17a of a housing 17. In the embodiment the spray nozzle
12 is provided with a spherical coupling which is urged against a
gasket 19 inside a chamber 20 which is supplied with compressed air
in the direction of the arrow 21 on the side where the gasket 19 is
situated. On the bottom on which the gasket 19 also lies, the
chamber 20 is connected with a connecting passage 22 which leads to
a housing part inside the housing 17, in which a control piston 23
is disposed. In this portion of the housing 17 a first end 24 of
the control piston 23 is guided with a piston ring 25 in a
cylindrical section 26 which separates a first chamber 27 from a
second chamber 28.
[0016] The first chamber 27 is supplied with a parting agent in the
direction of the arrow 29. The pressure of the parting agent is
applied to the face of the first end 24 of the control piston 23
and holds the control piston 23 in the position shown. At this
position, the control piston 23 abuts at its second end 30, which
has a greater diameter than the first end 24, against an abutment
on the right of the chamber 28. Between the free face of the second
piston-like end 30 and the housing 17 there remains a space 31
which can be fed with control air through a bore 32 in the
direction of the arrow 33 whenever a corresponding impulse is
present for supplying control air.
[0017] It can be seen that all compressed air connections (arrow
21) for parting agent (arrow 29) and for control air (arrow 33) are
provided on the same mounting surface 35 on the side of housing 17
facing away from the discharge opening 34 of the spray nozzle 12.
The housing 17 can thus be applied in a simple manner to spray arms
16 in the interior of which the corresponding feed passages run,
which in turn are in communication with the passages 4 to 7 in the
manner previously described.
[0018] The operation of the spray element of FIG. 2 is as
follows:
[0019] In the illustrated position of the control piston 23 the
connection to chamber 27 is closed. The parting agent is therefore
under pressure in this chamber. Compressed air can enter the
chamber 20 in the direction of arrow 21 and be discharged from the
orifice 34 of the spray nozzle 12, for example for blow-drying
purposes. It is however also possible in this condition to stop the
supply of compressed air from the exterior.
[0020] When control air is injected in the direction of arrow 33
into the chamber 31, the control piston 23 is shifted leftward from
its position in FIG. 1, while the sealing ring 25 comes out of the
cylindrical section 26 and the parting agent can enter under
pressure into the chamber 28 and from there can pass through the
connecting passage 22 into the space inside of the sealing ring 19.
The parting agent is therefore carried through the bore 36 in the
center of the spray nozzle 12 to its discharge orifice 34 where it
is fed by compressed air, which is fed in the direction of the
arrow 21, and exits from the bore 36 through passages 37, is
atomized, and is discharged in a spray.
[0021] If the spraying is to be stopped, the control air 33 is shut
off and the control piston 23 moves under the pressure of the
parting agent in the chamber 27 back to the position represented in
FIG. 2. At this position, the connection between chambers 28 and 27
is shut off and therefore no more parting agent can be fed, but a
withdrawing effect is exerted on the parting agent still within the
connecting passage 22.
[0022] Due to the reverse movement of the control piston to the
position shown in FIG. 2, after the sealing ring 25 enters the
cylindrical section 26, the volume of chamber 28 is increased, so
that the reverse suction effect acts also on bore 36 and the
parting agent is securely prevented from undesirably dripping and
spraying.
[0023] As already mentioned, the system can be used also with the
parting agent feed shut off, in order to blow the molds dry, that
is, in case compressed air exclusively is blown in the direction of
arrow 21, unaccompanied by parting agent.
[0024] The foregoing disclosure has been set forth merely to
illustrate the invention and is not intended to be limiting. Since
modifications of the disclosed embodiments incorporating the spirit
and substance of the invention may occur to persons skilled in the
art, the invention should be construed to include everything within
the scope of the appended claims and equivalents thereof.
* * * * *